Non-redundant safety monitoring for an electric drive mechanism (with a sensor)

Abstract

The invention relates to a method for detecting undesired operating conditions of a driving device. A sensor (50) that is transformer-coupled between a stator side and a rotor side is triggered by a control circuit (40) for detecting a position value or a rotational speed value of the drive mechanism. An error signal (F) is emitted, if an undesired operating condition occurs. A test signal (ε) is supplied to a safety monitoring device (30) in order to determine and emit this error signal (F), said test signal being also supplied to the control circuit (40). There, the test signal (ε) acts as an unbalance and is checked as regards its presence in the safety monitoring device.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application is a U.S. National Stage Application of International Application No. PCT / DE04 / 00240, filed Feb. 10, 2004, which claims the benefit of DE 103 05 337.9, filed on Feb. 10, 2003, the disclosures of which are incorporated by reference herein in their entireties. PCT / DE04 / 00240 designated the United States and was not published in English.FIELD OF THE DISCLOSURE[0002]The invention relates to a process for monitoring a drive mechanism that is in particular electrically driven and customarily consists of a driving motor, a shaft and an output coupled to the shaft. At least one measuring signal, mostly also several measuring signals, is and / or are required in such drive mechanisms, which are customarily designated as rotational speed, acceleration and position (or angle of rotation) in drive technology.[0003]The invention relates both to a process for detecting an undesired operating condition and to a sensor that is secured agai...

AI Technical Summary

Benefits of technology

[0007]According to an embodiment of the invention, a sensor is of a reliable safety providing the generation of an error signal via a monitoring circuit possible, a non-admissible operating condition being detected and the error signal being accordingly generated.

[0021]The use of the unbalance signal (also: test signal) for recognizing short circuits in the connecting leads, the connecting points or the winding of the sensor is advantageous. An interruption could at best be detected with an impressed one-polarity signal (Gleichsignal) in the sensor which does not have any influence on the measuring variable due to the transformer coupling, but not a short circuit which would leave the DC current signal at the sensor practically unchanged. The most frequent causes of trouble are defective cables and connections, which can be recognized with the invention irrespective of the type of the defect associated with the sensor.

[0024]According to the invention costs can be reduced by saving further redundant transducers. Assembly expenditure can be avoided and, nevertheless, safety can be obtained.

Problems solved by technology

Thus, this test signal influences the entire control circuit and, figuratively speaking, represents an unbalance, if one proceeds from the assumption that, in the stationary condition, a deviation of zero is present at the input of the controller of the circuit arrangement.

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